Rockwell Medical Inc reported positive results from a clinical study of its iron deficiency treatment for patients on hemodialysis.
The company's shares, which rose 25 percent in early trading, later pared some gains to trade up 4 percent at $6.70.
The study was not part of Rockwell's pivotal program to get U.S. Food and Drug Administration approval for the drug, company spokesman David Connolly said. He said Rockwell would use the results to market the drug if approved.
The drug, Soluble Ferric Pyrophosphate (SFP), is being tested in two late-stage trials as a treatment for iron deficiency in patients on hemodialysis - the process of removing wastes and extra fluid from the blood of patients with kidney failure.
Rockwell said the study results announced on Monday showed regular administration of its treatment reduced the need for erythropoietin stimulating agents (ESAs), which are used to stimulate red blood cell production, by 37 percent.
"This doesn't get them any closer to the approval," said Zacks Investment Research analyst Brian Marckx.
"This essentially says that SFP may not necessarily be inferior to intravenous (IV) iron in reducing the amount of ESA used. It doesn't say that it's better than IV iron," he said.
Results of the FDA-approved trials are expected in the second half of 2013. Connolly said that Rockwell expected to file for marketing approval by the end of the year.
Rockwell is also testing SFP in early-stage trials for three other mediums of delivery - oral, peritoneal dialysis and total parenteral nutrition.
(Reporting by Esha Dey and Vrinda Manocha in Bangalore; Editing by Roshni Menon)